Sunshine and Stock Returns: Weather Effects in Frankfurt
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Sunshine and Stock returns: Weather effects in Frankfurt V. Bouten1 Supervised by dr. J.J. Bosma Master thesis University of Groningen June 2018 Abstract This paper examines the presence of both rational and behavioral weather effects on stock market returns. The existence of weather effects has been tested by adding sunshine as a variable in the Fama-French three-factor model. It was hypothesized that government policy on renewable energy generation would engender rational weather effects. Behavioral weather effects resulting from changes in investor optimism were expected to be absent. This study utilizes panel data on 399 equities listed on the Frankfurt stock exchange from 1995-2017. The findings did not support the presence of either type of weather effects. Keywords: Stock prices, weather, government policy JEL codes: G12, G41, Q48 1 Corresponding author: Valentijn Bouten, student MSc. Finance and Msc. Economics at the University of Groningen. Postal address: University of Groningen, Faculty of Economics and Business, Nettelbosje 2, P.O. Box 800, 9700 AV Groningen, The Netherlands. Email: [email protected]. Introduction In traditional finance theory, the efficient market hypothesis (EMH) claims that market participants are rational and that the securities markets only reflect relevant economic information. These assumptions imply that all assets are correctly priced and that future stock prices follow a random walk pattern. Therefore, it is not possible to earn abnormal returns from mispricing according to the EMH. Yet, multiple researchers have documented patterns in the market that appear to violate the assumptions of the EMH (e.g., French, 1980; Jones and Litzenberger; 1970, Thaler, 1987). One of the alleged anomalies is the phenomenon called “weather effects”, where stock market prices are influenced by the weather conditions (Cao and Wei, 2005; Hirshleifer and Shumway, 2003; Saunders, 1993). Saunders (1993) was the first to document weather effects by investigating the relationship between New York City weather and Wall Street stock returns. The empirical results indicated a negative correlation between cloud cover and stock returns. The paper referred to psychology literature to explain the observed correlation. It was argued that favorable weather conditions (e.g., sunshine) positively impact mood states and, consequently, increases optimism among investors. Hirshleifer and Shumway (2003) extended Saunders’ work by investigating the presence of weather effects in 26 countries all over the world. Again, correlations between weather and stock returns were observed and contributed to the same psychological link between weather and optimism. Interestingly, Hirshleifer and Shumway (2003) even claimed that weather-based trading strategies could be profitable under very low transaction costs. Nonetheless, the claim that weather effects are indeed market anomalies remains debatable. First of all, the conclusions on weather effects are mostly based on standard regression results with little financial controls. In fact, Trombley (1997) even argued that the significance of the results on weather effects heavily rely on variable specifications. Furthermore, the potential of rational explanations for the observed correlations between weather and stock returns have received little attention. In traditional finance theory, markets and agents are rational; therefore, a link between weather and stock returns is only possible if weather conditions contain new relevant economic information. Previous studies on weather effects argue that weather information is economically irrelevant; therefore, any potential weather effects reflect irrational behavior of financial agents (Saunders, 1993). Yet, a rational explanation for a correlation between weather and stock returns might be very compelling in some cases. 2 In this paper, the research question ‘Does the weather impact stock market returns?’ will be critically examined utilizing a panel dataset. Both the potential of behavioral and rational weather effects on the Frankfurt stock exchange returns will be investigated. The different types of weather effects enable us to examine if weather effects are strictly an anomaly in the efficient market hypothesis. According to the rationality assumptions in the EMH, investor behavior should not be affected by the weather. Hence, it is hypothesized that there are no behavioral weather effects. For potential rational weather effects, the impact of government policy on renewable energy firms will be examined. In order to stimulate the development of the renewable energy industry, governments provide financial incentives linked to the generation of renewable energy. The financial incentives create a more favorable investment environment, which hypothetically beneficially impacts the capital allocation towards the renewable energy sector. More specifically, feed-in tariffs on solar energy generation imply that the amount of subsidies and/or tax credits received increases on sunny days. Therefore, the attractiveness of solar energy stocks increases. Thus, the government policy on renewable energy is expected to engender (rational) weather effects; higher stock returns on sunny days. In this case, however, the explanation will not be based on psychology, but on rational economics. Hence, these weather effects resulting from government policy will not violate the EMH and traditional finance theory. The data analysis focuses on the relationship between sunshine and equity returns on the Frankfurt stock exchange from 1995 to 2017. The Fama-French three-factor model will be used as the main benchmark to model variation in stock price returns. The Fama-French three-factor model contains a size factor, a value factor, and a market risk factor. These three factors jointly explain approximately 90 percent of the variation in expected returns of a standardized set of portfolios (Fama, French, 1993). Weather will be added as a control variable in the Fama-French model to assess the impact of weather on asset pricing. Furthermore, a policy variable will be included to examine the impact of rational weather effects resulting from government policy on renewable energy. The results do not provide strong evidence for the presence of either type of weather effects. Multiple model specifications do indicate significant rational weather effects, but these findings are very small and reliant on model specification. Therefore, the real impact of this observed relationship is likely to be negligible. In the next section you will find a review of previous relevant literature. The sections after that will discuss the data and methodology utilized in the analysis, respectively. 3 The results from the empirical analysis will be presented in the results section along with multiple robustness checks. Finally, a conclusion section with the most important findings in this paper will follow. Literature review Several studies have documented weather effects on stock markets (Cao and Wei, 2005; Hirshleifer and Shumway, 2003; Saunders, 1993). One of the first researches on weather effects was performed by Saunders (1993) on the effects of the New York weather on stock exchange returns. The research focused on four different time samples ranging from 1927 to 1989. Daily percentage of cloud cover was utilized as the weather variable, because of the highly correlations with sunshine, humidity, and precipitation. The percentages of cloud cover were grouped into three categories: 0-20%, 30-90%, and 100%, reflecting clear days, partially clouded days, and clouded days, respectively. A simple regression with monthly controls indicated a significant relationship between cloud cover and stock returns for two of the four time samples. To explain the relationship between weather and stock returns, Saunders (1993) refers to literature in psychology. Multiple studies have indicated effects of weather conditions on individual mood states (e.g., Bell, 1981; Cunningham, 1979; Howarth and Hoffman, 1984). Furthermore, sunlight has been linked to increased optimism (Howarth and Hoffman, 1984). The increased optimism amongst investors due to sunlight will explain the observed correlation between weather and stock returns (Saunders, 1993). To support the behavioral explanation for weather effects, Saunders (1993) argues that weather is economically irrelevant in rational markets due to diversification. Furthermore, the author refers to a paper by Richard Roll (1984), who found only a small impact of weather on orange juice futures pricing in Florida. According to Saunders (1993), this directly illustrates the economic irrelevance of weather; therefore, any significant relationship between the weather and stock prices illustrates an irrational behavior by financial agents. Hirshleifer and Shumway (2003) extended Saunders’ work (1993) by investigating the weather effects in 26 countries all over the world. Effectively the same theoretical framework on (behavioral) weather effects was utilized. The effect of morning sunshine in the city of a country’s leading stock exchange was investigated for the period 1982- 1997. The authors utilized simple regressions along with a logit regression on the probability of positive returns. The regression models included controls for seasonality and extreme weather conditions. The findings for the pooled data indicated a significant, negative relationship between (morning) cloud cover and stock returns. In the analysis 4 on each individual country, the data